US2986101A

US2986101A - Snubbed truck

Info

Publication number: US2986101A
Application number: US790758A
Authority: US
Inventors: Carl E Tack; Fred E Bachman; Arthur F Baker
Original assignee: American Steel Foundries
Current assignee: American Steel Foundries
Priority date: 1959-02-02
Filing date: 1959-02-02
Publication date: 1961-05-30
Anticipated expiration: 1978-05-30

Description

y 1961 c. E. TACK ETAL 2,986,101

SNUBBED TRUCK Filed Feb. 2, 1959 4 Sheets-Sheet 1 a l W J i 0 i 20 5 57 May 30, 1961 c. E. TACK ETAL SNUBBED TRUCK 4 Sheets-Sheet 2 Filed Feb. 2, 1959 hi fl l l U. a

y 0, 1961 c. E. TACK ETAL 2,986,101

SNUBBED TRUCK File Feb- 2. 1959 4 Sheets-Sheet a y 1961 c. E. TACK EI'AL 2,986,101

SNUBBED TRUCK Filed 2, 1959 4 Sheets-Sheet 4 United States Patent SNUBBED TRUCK Carl E. Tack, Chicago, and Fred E. Bachman and Arthur F. Baker, Granite City, [1]., assignors to American Steel Foundries, Chicago, Ill., a corporation of New Jersey Filed Feb. 2, 1959, Ser. No. 790,758

23 Claims. (Cl. 105-197) This invention relates to railway car trucks and more particularly to a novel snubbed bolster truck wherein friction means are provided for damping vertical and horizontal oscillation of the bolster relative to the side frames affording spring-support for the ends of the bolster.

A primary object of the invention is to devise a snubbed truck in which the friction means may be quickly and easily assembled and disassembled with the bolster resting on its supporting springs.

A more specific object of the invention is to enable a single operator to assemble or remove the friction means from the outboard end of the bolster without jacking the latter from its supporting springs and without moving the bolster in any manner whatsoever.

Another object of the invention is to compress the actuating spring for the friction means against a spring seat having a simple and effective releasable interlock with the bolster at its outboard end.

Still another object of the invention is to devise novel means for compressing the actuating spring to enable release of the removable spring seat from the bolster.

The foregoing and other objects and advantages of the invention will become apparent from a consideration of the following specification and the accompanying drawings, wherein:

Figure 1 is a fragmentary perspective view of a freight car truck embodying a preferred form of the invention, the view being taken from one outboard end of the bolster;

Figure 2 is a fragmentary top plan view of the structure shown in Figure 1 with the side frame columns shown in horizontal section and the spring plate retainer key broken away;

Figure 3 is a sectional view on line 3-3 of Figure 2 illustrating use of cam mechanism prior to insertion of y;

Figure 4 is a sectional view on line 4-4 of Figure 2;

Figure 5 is a fragmentary perspective view similar to Figure 1, showing the application of a cam mechanism utilized in the assembly and disassembly of the friction means;

Figure 6 is a fragmentary perspective View taken from the outboard end of the bolster with the friction means removed therefrom;

Figure 7 is a fragmentary perspective view similar to Figure l but showing a modification of the invention;

Figure 8 is a fragmentary top plan view of the structure shown in Figure 7;

Figure 9 is an elevation view taken on line 9-9 of Figure 8;

Figure 10 is a sectional view taken on line 10-10 of Figure 8;

Figure 11 is a fragmentary perspective view similar to Figure 1, but showing another modification of the invention;

Figure 12 is a fragmentary top plan view of the structure shown in Figure 11;

2,986,101 Patented May 30, 1961 ice Figure 13 is a sectional view on line 13--13 of Figure 12;

Figure 14 is an outboard end elevational view showing the structure of Figure 11 with a tool applied to the bolster end for assembling and disassembling the friction means;

Fig. 15 is a fragmentary perspective view similar to Figure 1, but showing still another embodiment of the invention;

Figure 16 is a fragment top plan view of portions of a truck embodying still another form of the invention, and

Figure 17 is a front elevational view of the structure illustrated in Figure 16.

Describing the invention in detail and referring first to the embodiment thereof illustrated in Figures 1-6, the bolster, generally designated at 2, is illustrated as a onepiece structure; however, it will be readily understood by those skilled in the art, that if desired, the bolster may be a composite structure composed of separable components which, when assembled on the bolster supporting springs, oscillate as a unit. The bolster is spring-supported as at 3 from a side frame 4.

The bolster comprises top and

bottom walls

5 and 6 and spaced

side walls

8 and 9. The side walls and the top and bottom walls define an opening 10 in the outboard end of the bolster 2 through which a friction shoe 12 and its actuating spring 14 may be conveniently assembled and disassembled, as hereinafter described, without the necessity of moving the bolster in any manner whatsoever.

The shoe 12 extends through an opening 15 of the side wall 8 and bears against a friction surface 16 of a side frame column 18. The shoe also bears against a seat or web 20 of the bolster as best seen in Figures 2 and 4. The web 20, as illustrated in Figure 4, is of the socalled double angle type defining a V between the top and

bottom bolster walls

5 and 6, thus interlocking the bolster 2 and shoe 12 against relative vertical movement or chatter during oscillation of the bolster in service. However, it will be understood that if desired, the web 20 may be of the so-called single angle style, shown in US. Letters Patent No. 2,730,049 issued on January 10, 1956, to Schlegel, or, if desired, the bolster web 20 may be vertical or of any other suitable configuration.

The shoe comprises a spring seat 22 (Figure 2) facing the bolster opening 10, and the seat 22 is engaged by the compression spring 14, the outboard end of which is seated against a spring seat 26 removably attached to the bolster 2 by a key 28 extending through slots or apertures in the top and

bottom bolster walls

5 and 6. The key comprises a head 30 for convenient handling and extends through a loop or strap 32 of the spring seat 26. If desired, a retainer such as a pin (not shown) may be inserted through aligned openings (not shown) of the key 28 and the strap 32 to prevent any possibility of accidental displacement of the key in service.

Reaction of the spring 14 through the shoe 12 and the bolster web 20 urges the bolster transversely thereof into frictional engagement with a friction plate 34 on a column 36 of the side frame 4.

In assembling the friction device, the shoe '12 is inserted through the bolster opening 15 and is manually urged to the position shown in Figure 2 in snug abutment with the bolster web 20 and the column surface 16. The spring 14 is manually seated against the spring seat 22 of the shoe 12 and against the spring seat 26 in the position shown in Figure 3. The spring 14 is then compressed by cam plates 37 which, as best seen in Figures 3 and 5, straddle the loop 32 and bear against the outboard side of the spring seat 26. The cam plates 37 are inter-connected by a trunnion 38 which is releasably journaled in a socket 40 of a lug 42 depending from the top bolster wall at the outboard end thereof. As best seen in Figures 3 and 5, the socket 40 faces inboardly toward the spring seat 26, whereby exertion of a downward force on a cam lever 44 connected to the plates 37, the spring seat 26 is urged beyond the position shown in Figure 3, thereby compressing the shoe actuating spring 14 to a point whereat the key 28 may be dropped into assembled position shown in Figures 1, 2, and 5 of the drawings. The cam lever is then released so that the spring 14 urges the key 28 into tight abutment between spring seat 26 and top and

bottom bolster walls

5 and 6. In reverse manner, the friction shoe 12 and spring 14 may be removed, as for replacement or repair.

Referring now to Figures 7-10, inclusive, a modification of the novel truck is illustrated, wherein parts corresponding to those previously described are identified by corresponding numerals.

In the modification, the opening in the outboard end of the bolster is partly defined by

vertical ribs

50 and 52, and compression of the spring 14 is maintained by a readily releasable spring plate 54 received within a slot 56 in the top bolster wall 5. The plate 54 comprises a slot 58 partly defined by

spaced legs

60 and 62 received within complementary apertures of the bottom bolster wall 6, as best seen in Figures 9 and 10.

The friction device, consisting of shoe 12 and its actuating spring 14, may be quickly and conveniently removed by means of a bolt 66 having a T-head 68 which may be inserted through a complementary slot 70 of the friction shoe and may be rotated 90 and retracted slightly to the position shown in Figure 8 to interlock the head and the bolt against rotation by engagement by the head 68 with lugs 72 of the friction shoe, as shown in Figure 8. Thereafter, a nut 74 on the bolt 66 may be rotated by a wrench or other suitable tool (not shown) to compress the spring 14 between the shoe spring seat 22 and a spring seat 76 sleeved on the bolt 66 and slidably engaged with the nut 74. When the spring has been compressed to a point at which the plate 54 can be lifted from the bolster slot 56 by means of a handle 78 on the top of the plate 54, the latter is disassembled in this manner from the bolster and the spring 14 and shoe 12, together with the bolt 66, the nut 74, and the spring seat 76, may be pulled through the opening 10 in the outboard end of the bolster to completely disassemble the friction device without moving the bolster in any manner whatsoever.

In reverse manner, the friction shoe 12 and spring 14 can be assembled with the bolster and when the nut 74 has been rotated to a point whereat all reaction of the spring 14, is transmitted to the bolster by the spring plate 54, as shown in Figure 10, the nut may be additionally rotated to permit inward movement of the bolt to a point whereat the head 68 is released from the shoe lugs 72 whereupon the bolt may be rotated until the head can be pulled outwardly through the slot 70 so that the bolt 66 and nut 74 may be completely removed from the truck whereupon the latter is in condition for service. Accidental upward displacement of the plate 54 under these conditions is prevented by an overlying ledge 79 of the top bolster wall 5.

Figures 11-14, inclusive, illustrate another embodiment of the invention and parts corresponding to those previously described are identified by corresponding numerals.

In this modification the outboard end of the spring 14 is compressed against a spring seat 100 having one end received in a slot 102 of the bottom bolster wall 6. The spring seat 100 is seated against the bottom wall 6 along a ledge or shoulder 104 of the spring seat 100. The other end of the spring seat extends upwardly through a slot or aperture 106 of the top bolster wall 5. The spring seat comprises a ledge or shoulder 108 underlying ignated at 120.

the top bolster wall 5, as best seen in Figure 13, to afford a positive interlock between the bolster and spring seat 100 preventing accidental upward movement thereof in the assembled condition of the friction shoe 12 and spring 14 shown in the drawings. In the event that the friction shoe 12 or spring 14 should become broken in service, relieving the seat 100 of spring pressure, it will be apparent that the seat 100 will remain in position preventing accidental loss of the spring or shoe from the opening 10 in the outboard end of the bolster. The only manner in which the spring seat 100 could accidentally become disassembled from the bolster in the event that the seat is relieved of spring pressure would be if the spring seat 100 became seated at its lower end on the bottom bolster wall 6 in a perfectly vertical position with the ledge 108 aligned with the forward edge of the aperture 106 at a time when the spring seat 100 is subjected to a perfectly vertical upward impact. Such a combination of circumstances is so unlikely as to be almost hypothetical.

The bolster

walls

5 and 6 are provided with a depending lug 110 and an upstanding lug 112, respectively, affording abutment for lugs 114 and 116 of a yoke 118 constituting part of a screw type jack, generally des- The jack comprises a pressure block 122 having side plates 124 which straddle the spring seat 100 and engage the outboard end of the spring 14, whereby upon rotation of a screw 126 threaded in the yoke 118 and rotatably journaled at 128 in the pressure block 122, the spring 14 may be compressed to a point whereat the spring seat may be manually removed through the slot 106 in the top bolster wall 105.

The friction device may be assembled by manually urging the shoe 12 and spring 14 to the position shown on Figure 12 and then compressing the spring 14 by means of the jack to a point at which the spring seat 100 may be inserted through the bolster slot 106 to the position shown in Figure 13, whereupon the jack 120 is actuated to release its pressure against the spring 14 until the latter urges the spring seat 100 into tight engagement with the bolster within its

apertures

102 and 106, as seen in Figure 13. Thereafter, the jack 120 may be moved laterally to disengage its lugs 114 and 116 from the bolster

lugs

110 and 112.

Figure 15 illustrates another embodiment of the invention which is substantially identical with that disclosed in Figures 11-14 hereof except that two friction devices, each consisting of a shoe 12 and spring 14, are provided; and a bolster mounted releasable spring seat 100, identical with that described in Figures ll-l4, is utilized to maintain pressure on each spring 14. It may also be noted that in the embodiment of Figure 15, the top and bottom bolster

walls

5 and 6 are provided with holes 130 for the purpose at anchoring an associated power type jack (not shown) which may be utilized to compress the springs 14 during assembly and disassembly of the friction devices substantially as heretofore described in connection with the embodiment of Figures 11-14.

Thus, it will be understood that the novel snubbed truck is simple and rugged in design, utilizing a minimum number of parts, with the friction device readily removable from an opening in the outboard end of the bolster without the necessity of jacking the bolster from its supporting springs or moving the bolster in any manner whatsoever. This greatly reduces the time required to assemble and disassemble the friction device and permits repair or renewal thereof under conditions where it would otherwise be impossible to service the friction devices.

Figures 16 and 17 illustrate still another embodiment of the invention. It will be seen that the arrangement illustrated in these figures is similar to that of Figure 15 except that the friction shoes 212 have been provided with extra large outer friction flanges 213 to afford greater areas of frictional engagement between the bolster and the side frame, and the bolster and side frame have been altered to accommodate the use of these modified friction shoes.

As best seen in Figure 16, bolster side walls 208 and 209 terminate at the rearward extremities of webs 220 so that forwardly of this point, on each side of the bolster, there is an opening 215 provided between the upper and

lower walls

205 and 206, respectively, of the bolster, which extends all the way to the outboard end of the bolster.

As best seen in Figure 17, the flanges 213 of each shoe extend above and below the inner surfaces of bolster top and

bottom walls

205 and 206 so as to preclude insertion or withdrawal through the bolster opening 215 in the same manner that the friction shoes 12 of the other embodiments of the invention are inserted or withdrawn through related bolster openings 15 of those embodiments. However, by extending the opening 215 all the way to the outboard extremity of the bolster, it will be seen that after the friction springs 214 have been removed in the same manner as those of the embodiments illustrated in Figures 14 and 15, the friction shoes may be withdrawn from the bolster by sliding them straight out along a line parallel to the longitudinal axis of the bolster.

In order to compensate for any loss of rigidity occasioned by the elongation of openings 215, there may be provided a vertical center wall 207 which is formed integrally with, so as to interconnect, bolster top and

bottom walls

205 and 206.

It will also be apparent from an examination of Figures 16 and 17 that if the bolster were provided with conventional gibs disposed on opposite sides of side frame column 218, the outboard gib would preclude the withdrawal or insertion of the flanged shoes 212 in the manner previously described. Thus, in order to accommodate assembly of the shoes in this manner, the bolster has been provided with a pair of extra large single inboard gibs which extend outwardly from side walls 208 and 209 at the place of their merger with webs 220. Each inboard gib 230 is received w'thin a slot 232 presented by a generally L-shaped lug 234 preferably formed integrally with the inboard side of related column 218. It will be understood that the embodiment illustrated in Figures 16 and 17 is basically the same in operation as the embodiment illustrated in Figure 15, and the friction device may be assembled and disassembled from the bolster in the same manner. A primary advantage of the embodiment illustrated in Figures 16 and 17, however, is that substantially greater areas of frictional contact are provided between the bolster and side frame by virtue of the enlarged friction shoe flanges; also the novel construction of the bolster side walls and gibs permits the use of shoes having such enlarged flanges.

We claim:

1. A railway car truck comprising a frame, a bolster structure spring-supported by said frame, an internal shoe seat in said structure arranged angularly to a friction surface on said frame, friction shoe means bearing against said seat and surface, said shoe means having a spring seat facing an opening in the outboard end of said bolster structure, spring means compressed against said seat, and a spring seat separable from and removably interlocked with said bolster structure, said separable seat engaging the outboard end of said spring means to releasably maintain the latter under compression, the length and width of said opening being greater than the height and width of the spring means and shoe means, whereby said spring means and shoe means can be removed through said opening upon disassembly of the separable spring seat from said structure.

2. In a railway car truck, a frame, a hollow bolster structure having a top wall and a bottom wall springsupported by said frame, friction means in the bolster structure engaged with friction means of the frame for damping oscillation of the bolster structure, an opening in the outboard end of said structure between said walls, the opening being of greater height and width than that of said first-mentioned friction means, and means releasably interlocked with the bolster structure and disposed outboardly of said friction means for preventing removal thereof through said opening and said thirdmentioned means being readily separable from the bolster structure to permit removal of said first-mentioned friction means from the bolster structure through said openmg.

3. In a railway car truck, a frame, a bolster structure spring-supported thereby, friction means housed in said structure engaging friction means of the frame to damp oscillation of said structure, an opening in said bolster larger than the cross-sectional area of the first mentioned friction means to afford passage thereof through said opening without moving the structure in any manner whatsoever, and means releasably interlocked with the bolster for obstructing said opening and for holding the first mentioned friction means in engagement with the second mentioned friction means.

4. In a railway car truck, a frame, a bolster structure spring-supported by the frame, friction means housed in the bolster structure and projecting through an opening thereof into frictional engagement with the frame, a spring having a substantially horizontal axis, said spring being compressed at its inboard end against the friction means for actuation thereof, and readily releasable means releasably interlocked with the bolster structure for maintaining compression on the outboard end of the spring, said releasable means being movable vertically in unison with the bolster structure during vertical oscillation thereof.

5. A railway car truck according to claim 4, wherein the bolster structure and the pressure maintaining means are provided with interengaging means preventing accidental disassembly of the pressure maintaining means.

6. In a railway car truck, a frame, a bolster structure spring-supported thereby, friction means housed in the bolster structure and having frictional engagement with the frame, spring means compressed at its inboard end against the friction means for actuation thereof, readily releasable spring seat means releasably interlocked with the bolster structure and readily separable therefrom, the outboard end of said spring means being compressed against said spring seat means and urging the latter into tight abutment with the bolster structure.

7. A railway car truck according to claim 6, wherein the spring seat means is assembled and disassembled with respect to the bolster structure by movement through an aperture in the top thereof, and wherein the spring seat means comprises a surface underlying a surface of the bolster to prevent accidental upward movement of the spring seat means from assembled position thereof.

8. In a railway car truck, a frame, a bolster structure spring-supported by the frame, a friction shoe housed in the bolster structure in frictional engagement with the frame, a spring compressed against the shoe for actuation thereof, aspring seat maintaining compression on the spring, a plate releasably interlocked with the bolster structure and engaged with the spring seat, a slot in the plate, and means extending through the slot releasably interlocked with the shoe and engaged with the seat for compressing the latter against the spring to enable disassembly of the plate from the bolster structure.

9. In a railway car truck, a frame, a bolster structure spring-supported thereby, said structure comprising top and bottom walls and spaced side walls, one of the side walls being in frictional engagement with the frame, an opening through the other side wall, a friction shoe bearing against a surface of the bolster structure and extending through said side wall opening and frictionally engaging the frame, a slot through the top wall, a plate engaged with the bolster and removable through the slot, 3. slot through the plate intersecting the bottom thereof, spring means compressed between the shoe and the plate for actuation of the shoe, and means extending through the last mentioned slot connected to the shoe and the spring means for compressing the latter to relieve spring pressure against the plate and thereby accomodate removal thereof from the slot in the top bolster wall.

10. A railway car truck according to claim 9, wherein the plate comprises spaced legs partly defining its slot and received within apertures in the bottom bolster wall.

11. A railway car truck according to claim 9, wherein the plate underlies a surface of the top bolster wall to prevent upward movement of the plate when under pres sure by the spring means.

12. In a railway car truck, a frame, a bolster structure spring-supported by the frame, a friction shoe seated against a surface of the bolster structure and extending through an opening thereof into frictional engagement with the frame, said shoe having an outboardly facing surface, a spring seat having an inboardly facing surface, spring means compressed against said surfaces for actuation of the shoe, and readily releasable means engaging and interconnecting the spring seat and the bolster structure for maintaining compression on the spring means, the bolster having an opening in its outboard end larger than the height and width of the spring means and shoe to accommodate removal thereof through said opening upon release of said readily releasable means from the bolster structure.

13. A railway car truck according to claim 12, wherein the readily releasable means comprises a key extending through a loop of the spring seat and extending through openings of the bolster structure above and below said loop.

14. A railway car truck according to claim 13, wherein the bolster structure is provided with an abutment facing inboardly and engageable with a tool for compressing the spring seat against the Spring to enable disassembly of the readily releasable means from the bolster structure.

15. A railway car truck according to claim 13, wherein the readily releasable means are characterized by interengaged surfaces of the bolster structure and the second mentioned spring seat.

16. A railway car truck according to claim 15, wherein the spring seat is provided with an upwardly facing ledge underlying a portion of the bolster structure.

17. In a railway car truck having a frame member and a bolster member resiliently supported thereon, friction means carried by one of said members for engagement with a surface of the other member to damp relative vertical oscillation between the members, detachable spring retainer means carried by said one member in releasable interlocking engagement therewith, said retainer means being spaced from said friction means, spring means carried by said one member and compressibly interposed between the friction means and the retainer means, said spring means being operable to urge the friction means into engagement with said surface and to resiliently urge said spring retainer means into said interlocking engagement with said one member, said one member including means for releasably interlocking therewith a pressure device engageable with the spring means to compress the latter and permit removal of the spring retainer means, the spring means, and the friction means without chlanging the positions of the members relative to each ot er.

18. In a railway car truck, the combination of: a side frame having spaced columns defining a bolster opening therebetween and presenting opposed friction surfaces in said opening; a bolster having an end portion resiliently supported in said opening, said bolster having vertically spaced top and bottom walls interconnected by side walls, and an internal wedge wall presenting a wedge surface, at

least one of said side walls presenting in said bolster end portion a slot open toward the outboard extremity of the bolster; a friction shoe having portions disposed within and without said bolster, the outer portion of said shoe including a flange larger than said slot so as to be removable from the bolster only by sliding it in the slot toward the outboard end of the bolster; a spring compressibly abutting the inner portion of the shoe to urge it into engagement with the wedge and friction surfaces; and readily releasable spring seat means carried by the bolster in engagement with said spring.

19. In a railway car truck, the combination of: a side frame having spaced columns defining a bolster opening therebetween and presenting opposed friction surfaces in said opening; a bolster having an end portion resiliently supported in said opening, said bolster having vertically spaced top and bottom walls interconnected by side walls, and an internal wedge wall presenting a wedge surface, at least one of said walls presenting in said bolster end portion a slot open toward the outboard extremity of the bolster; a friction shoe having portions disposed within and without said bolster, the inner portion including a spring seat and wall engageable with the bolster wedge surface, and the outer portion including a flange engageable with a friction surface of the side frame, and a spring compressibly interposed between the shoe and the bolster operable to urge the shoe into engagement with the wedge and friction surfaces of the bolster and side frame, respecively, the slot in the bolster side wall permitting the removal of the shoe from the outboard end of the bolster.

20. In a railway car truck, the combination: a side frame having a bolster opening and presenting a vertical friction surface therein; a bolster resiliently supported in said opening, said bolster presenting an internal wedge surface diagonally related to the side frame friction surface, said bolster including a vertical side wall having a slot therein open at the outboard end of the bolster; a friction shoe disposed to extend through the slot, said shoe having an outer flanged portion disposed in engagement with said side frame surface and having an inner portion including a wall disposed in engagement with the bolster wedge surface; and resilient means compressed against the shoe to urge the shoe into engagement with the wedge and friction surfaces of the bolster and side frame; said slot accommodating removal of the shoe endwise of the bolster.

21. In a railway car truck, a frame having a supporting surface and a friction surface, a bolster spring carried on the supporting surface and movable adjacent said friction surface, said bolster having spaced abutments, a friction shoe disposed in said bolster and engaging the friction surface, spring means abutting said shoe and urging said shoe against said surface, and seat means abutting the spring means and being releasably maintained thereby against the abutments of the bolster, said spring means and shoe being removable from said bolster from between said abutments upon release of said seat means from the abutments.

22. In a railway car truck, a frame, a bolster springsupported on the frame, said bolster comprising vertically spaced walls interconnected by side walls and defining therewith an opening in the outboard end of the bolster, a friction shoe disposed between the walls and having a portion extending through an opening in one of the side walls inboardly of the first-mentioned opening and engaging the frame, an abutment on one of the bolster walls spaced from said second-mentioned opening and facing said second-mentioned opening, a releasable spring seat releasably engaging the abutment, a spring having its ends compressed against the shoe and seat respectively, and operable to maintain the engagement of the shoe with the frame and the engagement of the seat with the abutment, the shoe, spring, and seat being removable from between the walls through said opening.

23. In a railway car truck, a side frame having spaced 9 vertical members, a bolster spring-supported by the frame and having a portion disposed intermediate the members, said portion comprising vertically spaced walls and a wedge wall interconnecting said spaced walls adjacent one of the members and angling outboardly therefrom, a friction shoe disposed between said spaced walls, said shoe having a wedge surface and a friction surface, said wedge surface engaging the wedge wall and said friction surface engaging said one member, a spring seat, interlocking means on said spaced walls outboardly of said wedge wall and releasably engaging the seat to interlock said seat with said bolster, and spring means interposed be- 10 tween the shoe and the seat and urging said wedge surface into said engagement with the wedge wall and also urging said friction surface into said engagement with said one member, said shoe and spring means being removeable 5 from the outboard end of the bolster upon release of said seat from said interlocking means.

References Cited in the file of this patent UNITED STATES PATENTS 10 2,485,508 Pierce Oct. 18, 1949 2,669,944 Spenner Feb. 23, 1954 2,688,938 Kowalik Sept. 14, 1954 UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. 2,986,101 May 30, 1961 Carl E. Tack et ale It is hereby certified that error appears in the above numbered patent requiring correction and that the said Letters Patent should read as corrected below.

Column l line 54, for "af" read of column 7, line 7, for "accomodate" read vaccommodate column 8, line 19, after "said", first occurrence, insert side lines 28 and 29, for "respecively" read respectively line 31, after "combination" insert of Signed and sealed this 14th day of November 1961.

(SEAL) Attest:

ERNEST W. SWIDER DAVID L. LADD Attesting Officer Commissioner of Patents USCOMM-DC